The transport of natural ova and of ovum surrogates is being studied in the rabbit as a model system. Radioactive ovum surrogates are tracked with miniature radiation detectors. Instantaneous surrogate positions and velocity are derived. The velocity data is correlated with luminal pressure measurements on both sides of the moving surrogate. Visual recording of the tube allows the localized wall movements and contractile activity to be related to the luminal pressures. The studies are presently being carried out in extracted oviducts and will be extended to in vivo monitoring by means of implantable systems. A mathematical model of the dynamic-hydrodynamic system is programmed and being studied with the aid of simulated tubes and mechanically simulated wall activity.